[mbyron]

You were looking where you shouldn't have been, as others have said.

Even if you didn't see the goaltend/block, you can still help him when he comes to you. If it had been me, I would have said, "take a moment, replay it in your mind, and see whether the ball was coming down." Let him change his call if he wants to. Otherwise nod profusely as if you think he's right, and have him signal to count the basket.

If the coach asks, I would explain: "Coach, I clarified the rule for him, and he changed the call. I think we got it right." It's hard to complain about that.